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H. S. MAXIM. Dynamo-Electric Machine.

No. 228,543. Patented June 8,1880.

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'H. S. MAXIM. Dynamo-Electric Machine.

uonms PETERS co, PdOTO-LITHOY, wnsnmorou n c UNITED STATES PATENT OFFICE.

HIRAM s. MAXIM, or BROOKLYN, Assienon TO SPENCER n. SOHUYLER, on NEW YORK, n. Y.

DYNAMO-ELECTRIC MACHINE.

SPECIFICATION forming; part of Letters Patent No. 228,543, dated June 8, 1880; Application filed February 20, 1880. (Moth-l.)

To (LZZ whom it nmy concern.-

Be itknown that I. HIRAM S. MAXIM, of the city of Brooklyn, count-y ol' Kings, and State of New York, haveinvented certain new 5 and useful Improvementsin Dynamod llectric ltlachines, of which the following is a spceiiication, reference being had to the accompanying drawings, forming a part thereof.

My invention relates more particularly to a device for rcgulatingsuch machines in respect to the amount of electricity generated, so as to render the electro-motive force of the current constant at each point of consumption.

Dynamoelcctric machines, as they have I usually been constructed heretofore, have had no means of regulating the current, and this has constituted a seriousobjection to their use for many purposes to which electricity is applied. \Vhcre the current is all used in a single circuit and for a single purpose such machines have served the pn rposereasonably well; but they do not answer where many branches from a common circuit are used and each requires a definite and constant amount of ourrcnt, as in plating, telegraphing, and those systems of electric lighting where many lamps are worked in branches of the main circuit.

In plating fine goods much difficulty has been experienced from changes of polarity, as well as variations of quantity and intensity of the eurrent,even where a single bat-h has been used in a circuit. The electricity generated in the bath itself by the operation of plating is sometimes sufiicient to overcome the force of the field-magnets of the machine upon any slacking of speed of the machine, and reverse the current, and the removal of a part of the articles in course of plating frequently injures the remainder by causing too rapid a deposition of metal upon them.

It is extremely desirable in plating, telegraphy, electric lighting, and other applications of electricity, to generate alarge current at asinglecentral point and distribute it, much as water and gas are distributed, by mains and branches, in such a manner that the electromotive force of the current shall not vary at any point of consumption, however much its consumption may fluctuate.

50 Devices of various forms have been used for varying the resistance in the circuitto compensate for changes ofstrength in the current and for diverting apart of the current upon its increasing beyond its normal strength; but these systems of regulation involve great waste of power, and the devices employed are not sufticiently sensitive to fluctuations in the current to act eflicientl y. \Vhere increased resistance is thrown into the main circuit to compensate for a lamp or branch removed, it is obvious 6Q that the power consumed in generating the current remains the same, whether many lamps or branches, or only one or two, are in use, and the power represented by the lamps or branches not in use is wasted. 6

It is obvious that the regulating device should be applied to the source of supply rather than to the en rrent after itis generated; and it is the object of my present invention to providearegulatororgovernorforthedynamomachine, that shall automatically control the generation of the current, so as to make the amount of electricity generated at all times equal to the amount required for use, without appreciable variation of intensity. I contemplate applying this system of regulation in a variety of ways; but my present invention relates particularly to using an auxiliary machine to excite the main field-magnets, and turning the brushes of the auxiliary machine toward and from the neutral points of their commutator by mechanism automatically controlled by a sensitive electro-magnet in a branch of the main circuit.

In the drawings, Figure 1 is a plan of the top of my machine. Fig. 2 is a longitudinal vertical section out near the center. Fig. 3 shows the arrangement and connection of the wires. Fig. 4 shows the positions of the commutator-brushes of the cxcitingmachiue.

A A A are electro-magnets. forming the magnetic field of the main machine. The three on the left, as shown in Fig. 3, have their south poles attached to acurved piece of iron which goes nearly half around the armature, 5 and the three on the right have their north poles attached to a similar piece of iron diametrically opposite.- B is an armature carrying coils of insulated wire arranged in any of the usual methods and revolving between the :00

field-magnets A A A. O is the commutator of the main machine. It convevst-he current G, and aifixedto a sleeve surrounding the shaft of the machine. J is a toothed sector aifixed to the same sleeve and engaging with the bevel-gear K.

L L is a double disk or wheel mounted upon the shaft M, which carries the gear K. It is attached to the shaft so'as to turn with it,

I but is freeto move vertically upon it a short distance. I

N is a wheel mounted upon the shaft Q, and

revolving between the edges of the disks L L,

so that either of them may be made to engage with it. The shaft Q is mounted in the bearings O O,'and is revolved continuously in the same direction by the pulleys P and j and the band 7:.

R is a lever controlling the vertical position of the disks L L.

Tis a strong electro-magnct in the circuit of the auxiliary machine, and S is its armature.

. U 'is a spring applied to push up the armature end of the lever R, and V is its adjustingscrew.

h is an eleetro-magnet of high resistance, placed in a branch of the main conductors, and t is its armature.

. Z is a lever carrying the armature i, and

having a spring, a, to balance the pull of the magnet h.

' 'The operation of the machine is as follows:

-Upon the revolution of the shaft the auxiliary machine, the circuitof which is always closed, generates a current of electric ty, which passes through the main field magnets, through the shunt 17 18, or themagnetT, according as the shunt is open or closed, and finally through the field-magnets of the auxiliary machine, as shown in Fig. 3. \Vhcn the shunt 17 18 is open the path of the current is from 1 to 6, inclusive, in the order of the numbers;"but when the shunt is closed the magnet T is out out, and the current follows 17 18 instead of 5 6 '3.

The opening and closing of the shunt are effected by the magnet h, with its armature and lever, placed in the branch 20 21 22 of the main circuit 20 24: The position of the shunt obviously determines the magnetic condition of T, and consequently'the position of the armature S. The lever It is so arranged that when the armature S is depressed the lower reference to the sector-J that when the lower disk engages with Nthe brushes will be turned toward the position shown in the dotted lines in Fig. 4., whilc, 'with the upper diskin contact, they will be turned toward the position shown by the fulllines in the same figure.

ing far-enoughto unmesh the gearing. There are two vertical points, diametrically opposite to each other on the commutatonwhere the brushes receive no current from the machine. It is convenient to designate these as theneu- 'tral' points of the commutator, although they correspond to the maguetiepolcs of the armature. The position of the brushes when at y A stop, 1 (D', in Fig. 2,)prevents the sector from turnsuch neutral points of the connnutatoris rep- It is evident that the magnet h effectually controls the amount of current generated by the main'machine by shifting the commutator-brushes of the auxiliary machine, for the amount of electricity generated by the main machine depends upon the degree of excitement of its field-magnets by the current of the,

auxiliary machine, and that depends upon the position of its commutator-brushes.

The magnet T is made of low resistance, so

as not to weaken the current-of the auxiliary machine too much; but the magnet h is made of high resistance, both to prevent any considerable part of the main current from passing through it and to render it very sensitive to fluctuations in the strength of the main circuit.

The lever Z is mounted, like a. scale-beam, upon knife-edge supports, and its vibrations are kept within narrow limits by means ofthe screws X and Y.

To make an electrical connection between the lever Z and the conductorr, I use a cup of mercury and a pendant ofiron directly under the center of the lever, as this does not throw the lever out of balance or require any 'ap'preeiable power to move it. One connection of the shunt is carried to the cup of mercury through the conductor v, and the other to the set-screw X through the'condu'ctor p and the post d, so that the shunt is closed when the lever Z is raised.

The tension of the spring a is so adjusted, by means of its adjusting-screw b, that it exactly balances the pull of h when a current of normal strength is passing, and the machine is then self-adjusting to any fluctnatibns of consumption of the current. The adjustment of the spring a determines the normal intensity of the current.

Theparticular form of theparts shown is not essential, and it is obvious that various adjustable devices other than the spring a and lever Z may be used for balancing the pull of the magnet'h.

When branches are put in between the main conductors, or the work of the main circuit is otherwise increased, the current is momentaril y weakened very slightly, the pull of the magnet h is diminished, and the spring a draws down its end of the lever and opens the shunt. The magnet T being excited, throws the lower disk L into gear, and revolves the brushes G G toward the point of maximum current on the commutator, and the current is strengthened until equilibrium is again established between the magnet hand the spring a. \Vhen the work of the main circuit is diminished the reverse operation takcs'place.

This device is very sensitive to variations of strength in the main circuit, and it acts at once withgrcat el'licieucyto increase or decrease the amount of electricity generated; for at the first operation of opening the shunt the magnet T is thrown into the auxiliary circuit, and weakens it by increasing the resistance, and the rapid revolution of the brushes toward the neutral points still further weakens the auxiliary circuit. This not only directly decreases the power of the main Iield'magnets, but reacts upon the auxiliary field-magnets to still further weaken the auxiliary circuit and the main field. Upon closing the shunt corresponding increments are accumulated. The electro -'motive force of the curr nt at any point of consumption is thus kept constant by causing the machine to generate precisely the amount required for use.

Accidental changes of polarity in the main circuit are obviously impossible, as the magnetic field of the main machine is independent of the main circuit.

It is obvious that the essential features of the regulating device above described are the automatic revolution of the brushes of the auxiliary machine relatively to the maximum and nentralpoints of its commutator, and the automatic control of the direction of such rev-' olution by the magnet h or its equivalent, acted upon by the main circuit.

The particular arrangement of the toothed sector, friction-wheels, and magnet which I have described as used for revolving the brushes is not essential, as various other mechanical devices may be used, under control of the magnet h, for imparting a reversible revolving movement to the brushes, and I do not wish to be limited to the particular device shown.

Other devices may also be used in place of the magnet h for opening and closing the shunt-as, for instance, a metallic rod expanding and contracting according as more or less heat is imparted to it by the main current; but I prefer the electro-magnet on account of its greater sensitiveness to changes in the strength of the current.

I am aware that regulators of various forms have been applied to an electrical circuit, con

sisting of shunts or resistance-coils operated by the heating effects of the current upon a strip of metal. placed in the circuit, or some equivalent device; but. such regulators are fundamentally different from the regulator I have described above, for; they are designed to throttle or partially divert a current already generated, while my regulator operates directly upon the source of supply.

I do not claim, however, the use of an auxiliary machine for exciting the field-magnets oi the main machineindependently of the regulating device; but,

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination of a dynamo electric machine and asimilar auxiliary machine, used for exciting the main field-magnets,with commntator-brushesmounted so as to turn freely and revolving automatically relatively to the points of maximum and minimum current on the commutator of the auxiliary machine in response to variations of tension in the main current, substantially as described.

2. A dynamo-electric machine having its field-magnets excited by a similar auxiliary machine, in combination with mechanism for revolving the commutator-brushesof the auxiliary machine to and from the neutral.

points of its commutator, and an electromagnet for controlling the direction of such revolution, which magnet is thrown into and out of an electrical circuit by a shunt operated by an electro magnet in the main circuit or a branch thereof, substantially as described.

3. The sector J, carrying the brushes II H, in combination with the pinion K, the movable disks L L, and the friction-wheel N, the said. wheel N revolving continuously in the same direction, substantially as described, and for the purposes set forth.

4. The combination of the electro magnet 71 with the eleetro-magnet 'I, the said magnet h being of high resistance and placed in a branch of the main circuit, and its armaturelever controlling the admission of an electrical current to the magnet T, and the said magnet T being of low resistance and operating mechanism for increasing and diminishing the amount of electricity generated by the main dynamo-electric machine, substantially as described.

5. The combination, in a dynamo electric machine, of the electro-magnet h and adjustable spring a, or equivalent device, ,for regulating the normal tension of the current, with commutator-brushes revolved automatically to and from the points of maximum current on the commutator by mechanism controlled by said electro-magnet, substantially as (1e scribed.

HIRAM S. MAXIM.

Witnesses:

A. B. FAIR'OHILD, L. E. CURTIS.

IOC 

